Telegraph signaling apparatus



Sept. 27, 1938. H y. |||GG|TT ET AL 2,131,322

TELEGRAPH SIGNALING APPARATUS Filed Feb. 21, 1935 5 sheets-Sheet 1 Harry Vernon Hlggett andl .Kenneth Lmdsay Wood Sept 27, 1938'- H. v. HIGGlTT ET A1. 2,131,322

' TELEGRAPH SIGNALING APPARATUS vFiled Feb. 21, 1955 5 sheets-sheet 2 7.6 {g2g/573g 79 2* 71Horry Vernon Hgget and Kenneth L mdsag Wood Mgg@ Muni- ,477@/1/5/ Sept 27, 1938- H. V. HlGGlTT ET Al. 2,131,322

TELEGRAPH S I GNAL INGl APPARATUS Filed Feb. 22|., 1955 5 Sheets-Sheet 3 wwf/vm? Hdrry Hernan Hgggeit qnd Kermeth'-Lindsay Wood mwm Sept 27, 1938. H. v. HIGGITT ET Al. 2,131,322

TELEGRAPH SIGNALING APPARATUS Filed Feb. 21, 1935 5 sheets-sneer 4 //VV/V70 Harry Vernon Hnggett and Kenneth I mdsuy Wood 'V Sept. 27, 193s. HVHIGGWTH AL .2,131,322

TELEGRAPH SIGNALING APPARATUS Filed Feb. 2l, 1935 5 Sheets-Sheet 5 u 103 M 106 F/ 102 11417 [14a I09a Horlry Vernon HLqgett a Kenneth Lmdscy Wood Patented Sept. 27, 1938 PATENT oFFlcE TELEGRAPH SIGNALING APPARATUS Harry Vernon Higgitt and Kenneth Lindsay Wood, London, England, assignors to Cable and Wireless Limited, London, England, a British Company Application February 21, 1935, Serial No. 7,646 In Great Britain March 23, 1934 9 claims. (,cl; nrs-17.5)

This invention` relates to telegraph signaling apparatus and more particularly to telegraph systems for signaling by means of double current f cable code signals, that is to say, by means ofY 51 theA Morse code in which the signals consist of electrical conditions which are made to persist for various time intervals; The double current cable code as usually employed in practice makes use.

of two diierent kinds of currents or electrical 10' conditions to represent the three signal elements dots, dashes and spaces; forexample, a dot is often representedby an electrical condition such as a marking current having a duration 012.100Y

4 per cent ci a signaling interval, a dash by a second T5' electrical condition such as a vspacing current having the same duration, and a space is represented by the rst electrical condition lasting ,for

50 per cent of a signaling interval followed by the second electrical condition lasting for the re- 2'0- maining 50 per cent oi the signaling interval.

In order to overcome interference in telegraphy and particularly in order to overcome the effects of atmospherics or fading in wireless telegraphy circuits, it is well known to arrangelfor signals 25 to be automatically repeated from a transmitting station after certain intervals and for the repeated signals to be inter-leaved with the first transmission of the signals and also` to arrange for. automatic comparison of the original transmission. 30 and the repeated signals at a receiving station.

The main obj-ect of the present invention is to apply the principle of automatic repetition and subsequent comparison ofthe repeated signals to double current cable code working.

Thus, according to the present invention,each double current cable code signal is sent once and then sent again after a predetermined period and if desired, a third or even more times. The signals may be sent singly, in which case the sig- I0` nals of the repetition become alternate with the rst transmission, or they may be sent in groups. Thus, the double current vcable code telegraph system may be arranged to operate in eiect ony two or more channels, the circuit being allotted ,1f to the differentchannels in sequence and in this case, a signal is transmitted during the periods belonging to one channel and is subsequently automatically repeated if it is only repeated once, the repeated signal is in effect sent on the second 50' channel, but if repeated-more than once, the repetitions are sent in the periods allocated to the channels other than the first channel. lFor this purpose, the original signal when transmitted is also stored and `the storing mechanism is ar-` ranged `todivest itself of the signals later and thereby to vcause the repetition 'of the signals during the second orother channel times. At'the receiving station, the signal rst received is stored for a suiiicient time to await the arrivalof the .Y repetition or repetitions of the signal when the 5` original transmission and the repetition or repetitions are applied simultaneouslygito a vreceiving apparatus for comparison purposes. The storage, both at the transmitting end and at the receiving end, may be effected by storing in con- 10 densers by means of suitable Ysynchronously-- operated switching gear for charging and `discharging the condensers. However, in bothrinn-v stances, the signals may be stored electromagnetically, 'for example by recording the signals 15 on a magnetic medium and subsequently, after a predetermined interval; causing that medium to operate electromagnetic pick-ups or transmitters which, at the transmitting station, cause the repetition of the signal to thelin-e and at the re- 2'()v ceivingstation cause the original received signal to be made "available for Y,comparison purposes upon the arrival of the repeated signal. However, any other convenient form of storage means may be employed. 5:

In order that the invention may beV clearly- 2 understood and readilyrcarried into effect some examples of transmitting and receiving arrangements in accordance with the invention in which the signal is repeated once only Will now be mor-e 30 fully described with reference to the accompanying drawings, in which:- g

Figure 1 is a circuit diagram of the sending arrangements employing condenser storage;

Figure 2 is a circuit diagram `ofthe receiving arrangements also -employing condenser storage;

Figure 3 is a diagram corresponding to the lower part of Figure 2, but in which the comparison relays are differently connected; Y

Figure 4 is a circuit diagramV of modified send- .6 ing arrangements provided with electromagnetic storage; 1 v,

Figure 5 is a similar transmitting circuit provided with relay storage;` Y

Figure 6 is a diagrammatic plan;

Figures 7 and 8 are elevations of details in two' positions illustrating mechanical or so-called "metal storage; and 1 Figure 9 is a diagram of the connections of a sending apparatus embodying such metal 5b" storage. v Y Y d Referring first of all to Figure 1 the sending circuit is similar to that describedwith reference to Figure 9 of the drawings accompanying Patent No, 1,925,756. Thus, two sets of Ycablelcode signal 5'? transmitting levers 2I, 22 and 21, 28 driven at equal speeds are provided. The primary signal transmitting levers are indicated generally at TS while the delayed transmitting levers are indicated generally at TD. There is also a pair of combining switches C1, C2 and a reversing switch RS. These elements are timed or operated in the same phase relationship as described in the said'pricr patent. The timing of the-two sets of transmitting levers TS and TD is as indicated by the circular arrows I, 2, 3. The timing of the combining switches C1 and C2 is indicated by the arrows 4, 5, 6, 1 and is the same asin Figure 9 of the drawings with the said prior patent. This also applies to the timing of the reversing switch RS as indicated by the arrows 8, 9.

In this case, the signal transmitter TS consists of a pair of relays, the coils I0, II of which are controlled respectively by the d ot and dash mechanism of a cable code transmitter used for transmitting the signals.

The delayed transmitter TD has its coils I2, I3 energized from the signals stored in the storage arrangement. The latter consists of a synchronously driven distributor switch with two sets of stationary contacts I4, I5 which are traversed by `pairs of brushes I6, I1, I8, I9. The latter are' rotated, for example by means of a phonic motor at such a speed that each makes contact with one of the distributor contacts I4, I5 during the time of one signal period. The brushes I6, I1 are the charging brushes and they make contact at about the middle of a signal period. Y

The two corresponding contacts of each set I4, I5 are connected to one of the storage condensers, all of which condensers have the opposite plates earthed and connected to the centre of the split battery SB. It will be noted that the charging brush I6 is connected to the tongue 2I of the dash relay of the transmitter TS, while the charging brush I1 is connected' to the tongue 22 of the dot relay of the transmitter TS. Therefore, the condensers 20 are charged in turn with a polarity which is positive or negative depending upon whether the signal is a dot, dash or space. Thus, if a space signal is sent, both of the relay tongues 2l, 22 will remain against their back butt contacts 23, 24. The contact 23 is connected to the positive of battery SB so that the brush I6 will charge its condenser 20a positively. On the other hand, the contact 24 is connected to the negative end of the battery SB so that the brush I1 will charge its condenser 2Gb negatively. In the case of a dot signal, the coil I0 draws down the tongue 22 on to the front butt contact 25; the latter is connected to the positive terminal of battery SB, and therefore in this case the brush I1 will charge its condenser 20h alsopositively. Finally, in the case of a dash signal, the coil II of the dash relay draws down its tongue 2I on to its front butt contact 26 so that now brushes I6 and I1 both charge their corresponding condensers 20a, 20h negatively.

The brushes I8, I9 are rotated at the same speed as the brushes I6 and I1 so that they come into contact with the contacts I5 connected to the condensers 2D at a definite interval after these condensers have been charged. Diagrammatically this interval is illustrated as three times the distance between a pair of distributor contacts, but in actual practice, the distributor may have a very large number of contacts, and the delay may be equal to a large number of signal periods.

When the discharging brushes I8, I9 make contact with segments I5, the condensers 20c and 28d connected to the distributor contacts I5 in contact with the brushes I8, I9 are discharged through these brushes and through the coils I2, I3 of the two polarized relays I2, I3 which in effect form the second cable code transmitter.

If a space signal has been stored, the condenser discharges cause the tongues 21, 28 of these two polarized relays to be brought against their spacing contacts 29, 3|]k although one of the tongues 21, 28, and sometimes both, will already be in Contact with the spacing contacts 29, 30. If a dot signal has been stored, the tongue 21 of the dot polarized relay is thrown over to its marking contact 3 I, while if a dash signal has been stored the tongue 28 of the dash polarized relay is thrown over to its marking contact 32.

It will be noted that the tongues 2|, 22 of the transmitting relay TS are connected respectively to the butt contact 33 of the combining switch C2 and the butt contact 34 of the combining switch C1, while the tongue 21 of the dot polarized relay I2 is connected to the butt contact 35 of the combining switch C1 and the tongue 28 of the dash polarized relay I3 is connected to the butt contact of the combining switch Cz. Therefore, the tongues 21, 28 of the two polarized relays control the repetition of the signal to the line L with the delay determined by the period of storage in the condensers 20. The discharge brushes I8, I9, are timed so that vthe tongues 21, 28 are connected to line in the middle of their signal periods. This is clearly seen by comparing on the one hand, the arrows 2, 5 and 8 and on the other hand, the arrows 3, 1 and 9.

The condensers 20 may be used alternately for storing dots and dashes respectively in which' case the dot and dash brushes I6 and I1 are placed on the distributor drum at opposite ends of a diameter. As an alternative, of course, separate banks of condensers may be provided for the dots and dashes.

Referring now to Figure 2 in which a receiving circuit is illustrated, the directly sent signals and the stored signals sent on the two channels have to be separated and the double current cable code signals received from the line are transformed into ordinary cable code. The receiver illustrated in Figure 2 is connected as described With reference to Figure 4 of the drawings accompanying United States Patent No. 2,029,071 dated Jan. 28, 1936. In addition, however, to the apparatus there illustrated, there is mechanism provided at the receiving station for storing the signals as received from the first or original transmission due to the transmitter TS and rendering those signals available when the repeated transmission from the transmitter TD arrives, so that the first or direct transmission and the repeated transmission may be compared directly. In Figure 2 the relays 31, 38, 39, 40 may be regarded as corresponding to the output relays ORAl, GRAZ, ORB1 and ORB2 in Figure 4 of the drawings accompanying the said prior specification. Thus, 31 and 39 are the dot receiving relays for the original and repeated signals and 38 and 4l) are the corresponding dash relays. When a dot arrives on the original transmission the winding 31 is energized, contacts 4I, 42 are closed and a further relay 43 is energized. Similarly, when a dash arrives on the original transmission, the contacts 44, 45 are closed and.

an additional relay 46 energized. .L The tongue 41 of the dot relay 43 -isfconnected directly through a resistance r1 to the dot charging brush 48, while the tongue 45 of the dash relay 46 is similarly connected througha resistance r2 to the dash charging brush56. The storage arrangements here consisting of two sets of contact segments 5|, 52, the charging brushes 48 and 56 and the discharging brushes 53, 54, with the condensers are similar to the storage arrangements in the sending apparatus shown in Figure 1, so that the condensers 55 are charged by the pair of brushes 48, 5D to a polarity depending upon whether the rst ororiginal transmission sends a space, dot or dash. Thus, it will be noted that when the dot relay 43 Vis not energized, its tongue rests against the backrcon'tact 56 which is connected to the negative terminal of the battery and then the brush 48 charges the corresponding condenser 55 negatively. Similarly, the front contact 51 of the relay 43 is connected to the positive terminal 'f of the battery while the respective back andfront contacts 58, 59 of the dash relay 46 aregconnected to positive and negative ends of the battery.

The discharging brushes 53, 54- lag behind the charging brushes 48 and 56 by the same time period as the discharging brushes I3, I6 of the sending apparatus lag behind the charging brushes I6, |1, and the brushes 53, 54 are connected to energize a pair of comparison relays 6D 6| at the instants when the discharging brushes 53, 54 make contact with the distributor segments 52. Suitable shaping condensers 62'and resistances 63 are connected across the windings on relays 66 and 6|.

Corresponding with the pair of comparison relays and 6|, there is another pair of comparison relays 64, allocated to the second or repeated transmission and whose windings are energized direct from the tongues 66, 61 andthe front contacts 68, 65 of the dot and dash output relays 39, 40 respectively. Therefore, the four comparison relays 60, 6|, 64, 65 are energized, the first pair 66, 6| by the direct transmission which has been subjected to storage Vin the condensers 55, and has therefore been delayed, and the other pair of relays 64, 65 are energized by the repeated transmission. 'Ihen as the delay in the direct transmission due to storage in the condensers 55 is the same as the delay of the repeated transmission in the condensers 26 of the sending apparatus, the two pairs of comparison relays 60, 6|, 64, 65 are actuated simultaneously by corresponding signals. These four comparison relays are connected tothe windings 10, 1| of a pair of iinal relays. In Figure 2 the connection of the relays 1U and 1| is shown as employed when fading occurs, while in Figure 3 the same relays are shown connected for use when atmospherics are prevalent.

If double current cable code signals are sent over a wireless circuit, it is convenient for the dots to be represented by a power transmission for per cent of a signaling interval, for dashes to be represented by ceasing to transmit power for 100 per cent of a signaling interval, and to represent spaces by transmitting power for 50 per cent of signaling interval followed by ceasing to transmit power for the remaining 50 per cent of the signaling interval. In such a system the result of fading is that dots are missed and extra dashes are received in their place. In Figure 2 the relays 66, 6h64, 65 are connected to thecoils-1l1,` 1|` of the finalA relaywhich may in fact bemagn'ets of a perforater Yiii-such` a Way -that false operation due to fading only.Y occurs when fading affects equallyy the cor-V responding signals in both the original and the repeated transmissions. Thus, the tongues 12, 13V of the two dot relays 6U, 64 Yare connected direct to the positive terminal `of the'battery, and- It will' be noticed that the tongue 16 of the dashv relay 65 is connected to the positive of the battery and its front contact 11 is connected direct tothe tongue 18 of the dash relay 6|, while the front contact 19 of the latter is connected to the winding 1| of the dash final relay, so that in effectfthe tongues 16 and 18 are-connected-in series, so that if one of these tongues is operated on a dot'signal due to fading, a false dash orspace will not be perforated by the perforator controlled by the windings 1U, 1|.

v The eifect of atmospherics is diiferent from the effects of fading, and consequently the four relays 60, 6|, 64, 65 are diierently connected to thenal relays 10, 1| to deal with atmospherics. The mode of connection is illustrated in Figure 3 from which it will be noted that the tongues 12,Y 13V of the dot relays are now connected in series to the winding 1| of the final dot relay, while the tongues. 16, 18 of the dash relays are now connected inV parallel to the winding 1| of the final dash relay. Generally speaking, b-yV suitable adjustment of the wireless apparatus it is possible to arrange that fading and atmospherics do not occur during the same period. In oth-v er words, during some periods the main trouble is due to fading, and during other periods it is due to atmospheric disturbances. VSuitable changeover switches may be provided for changing over from the form of connections shown in Figure 2 to those shown in Figure 3 and in fact if desired the relays 60 and 6| or the relays 64, 65 only may be connected in circuitfor fault testing purposes. Thus by providing a switch of the sun flower type with radial arms and circular rows of Contact studs providedwith four positions, the operator may at any time adopt the connection shown in Figure 2 or Figure 3 or connect in the relays 60 and 6| or the relays 64, 65 alone.

Sometimes it is necessary to make the inter- Val ,between the original transmission and the repeated transmission so long that the form of.k storage by means of condensers illustrated in Figures 1 and 2 becomes cumbersome. In that case both in the transmitting apparatus and in the receiving apparatus a form of electromagnetic storage may be provided in the place of the condenser storage. This form of storage is shown as applied to the transmitting apparatus in Figure 4. The general circuit here is the same as in Figure 1. The relays TS, TD, combining switches C1, C2, the reversing switch RS, and all their contacts are similarly connected and similarly numbered. The only difference in Figure 4 is the storing arrangements. In Figure 4 the tongue 22 of the dot transmitter and the tongue 2| of the dash transmitter are respectively connected to terminals of the windings of secondary polarized relays 80, 8|, the opposite terminals of which are connected together and earthed at 82.i

Thus, these secondary relays are operated when dots -or dashes-are transmittedfand their tongues ythrough a coil 95 fed with alternating current 83, respectively close circuits through a source of interrupted direct current shown as a battery 85 and motor driven interrupter 86. The tongues 83, 84 and their contacts 81, 88 are respectively in the circuits of magnets 89 and 98 which may be termed respectively dot and dash recording magnets. They are placed so as to be capable of locally magnetizing a moving band 9| of magnetic material such as a soft iron telegraphone strip when the interrupted direct current is caused to pass through them. The strip 9| is led over a pair of pulleys v92 driven by a phonic motor 93 and is of such a length and driven at such a speed that the desired storage period may be obtained. It is arrangedthat the magnetic condition in the strip 9| corresponding to dots set up by the magnet 89 occurs on a distinct part of the strip from the magnetic condition representing dashes set up by the magnet 98 so that even if the magnetic condition, as it will be in this case, is the same for dots and dashes, this does not interfere with the operation. The strip after leaving the dot recording magnet 89 passes round until it reaches an electromagnetic pick-up or transmitter 94 for the dots. It then passes which demagnetizes it. Then in its virgin state it passes to the dash recording magnet 98 and then travels around until it reaches the dash pick-up or electromagnet transmitter 96 and then passes to a further demagnetizing coil 91 at which point it completes its cycle. The dot pick-up 94 and dash pick-up 98 are connected to separate ampliers A1, A2 and separate rectiers R1, R2. The output currents from the two rectiers R1, Rz are supplied to the windings I2 and I3 of the two relays of the second set of cable code transmitting levers TD which is connected as in Figure 1. In this case, however, the relays I2, I3 are non-polarized since they have to be sensitive only to charge in theoutput rectied current from the rectiers R1, R2.

A similar electromagnetic storing arrangement may be used at the receiving end to replace the condensers in Figure 2, but the details of connections of such an electromagnetic storing device is clear without further description.

Other ornrs of electromagnetic storage comprising modifications of that described above may be employed, that is to say, the moving band may `be replaced by a disc slowly rotated in synchronism, having, if desired, separate magnetic discs for dots and dashes, or a single magnetic disc may be employed with the magnetic conditions corresponding to dots and dashes stored in the iron at different radii from the centre of the disc.

The same frequency of interrupted direct current may be used for dots and dashes as already pointed out, but it follows that if a different frequency were provided for dashes than that provided for dots, if the ampliers connected to the electromagnetic pick-ups were made selective to the respective frequencies, the same length of band or the same portion of the disc could be employed upon which the dot and dash electromagnetic recorders could be allowed to act.

In Figure 5 the use of yet another form of storage is illustrated. In this case the storage depends upon the actuation of the armatures of a number of polarized relays 91. It will be noticed that one side of the winding of each of these relays is connected to one of the distributor segments I4 upon which a pair of charging brushes I6, I1 bear as in Figure 1. The opposite terminals of the relay windings are all earthed as shown at 98. When the dash charging brush I6 or the dot charging brush I1 makes contact with one of the segments I4, the corresponding relay 91 is momentarily energized and its tongue 99 is drawn over to the mark contact |88 or to the space contact IDI-unless it were already there, and then remains against that contact. The tongues 99 of the relays are connected directly to the contact segments |5 which correspond to the discharging segments in Figure l. The segments I5 may be made of any desired length circumferentially. 'Ihe brushes `I8 and |9 corresponding to the discharging brushes in Figure 1 are in this case connected directly to the contact 36 of the combining switch C2 and to the contact 35 of the combining switch C1. Actually the dot and dash distributor segments I4 and I5 may be arranged as two separate banks. In other respects the circuit shown in Figure 5 is the same as in Figure 1 and corresponding reference characters have been employed.

The use of the moving pin system of storage in connection with the present invention is illustrated in Figures 6 to 9. The rim of a drum has two raised circumferential flanges I 82 shown developed in Figure 6. A series of pins |83 are mounted so as to slide axially in these flanges and make frictional engagement so that they remain in any axial position into which they are pushed. The polarized setting electromagnet |84 has a winding |85 and an` armature |86 with an operating point |81. The drum |82 is rotated synchronously at such a rate that the time of angular movement from one of the pins |83 to move away from the point of the armature |86 and for the next pin to move opposite it, is equal to one signal interval. If the coil |85 is energized when a pin |83 arrives opposite to it the armature |86 is swung about its pivot |88 into the path of the pin |83 and the limb |81 acting as an inclined plane or cam, slides the pin |83 down into the position shown in Figure 6 at |8311. After a predetermined number of signal intervals, the pin is moved round until it comes opposite a spring returned lever |89 shown in plan in Figure -and in elevation in two positions in Figures 7 and 8. If the pin |83 has not been pushed down by the armature |86, it fails to coact with the lever |89 altogether and the latter remains in the position indicated in Figure 8. If, however, the pin |83 has been pushed into the position shown at |83a, the upper part of its cylindrical surface slides under the inclined nose ||8 of the end of the lever |89 and raised this end against the tension of a spring about a pivot ||2. In this position, the lever |89 makes contact with a lower contact I I4, otherwise as shown in Figure '1, it remains in Contact with an upper contact ||3.

In employing this device in a transmitter in accordance with the present invention, two such units are employed, the levers of which are shown in Figure 9 at |09a and |8921 the two coils being shown at |85a and |05b. It will be noticed that these coils are connected respectively to the tongues 22 and 2| of the cable code transmitter relays while the opposite ends of both of the coils |8511, and |85b are earthed. If a dot signal arrives, the coil |85a is energized and displaces the pin |83 which happens to be at that moment opposite its armature. Similarly if a dash signal arrives, the pin |83 in the drum actuated by the dash signals is displaced. As the two drums ro-- tate and the pins come round, the levers |89a,

11D9!) are brought down on to their lower contacts lllla, Il4b so that the positive and negative terminals of the split battery SB are respectively connected to the contact 35 ofv the combining switch C1 and the Contact 36 of the combining switch C2. The transmitter TS is connected to theseswitches exactly as in Figure l and these switches in turn are connected to the reversing switch RS in the same way as in Figure 1.

1. A telegraph signaling system for receiving double current cable code signals of the type set forth, comprising in combination, a receiving relay for receiving a transmission of signals on one channel and a delayed transmission of signals on a separate channel, switching means for converting both transmissions of Ydouble current cable code signals into cable code signals, a signal impulse storage device operatively connected to said switching means for receiving and storing the undelayed transmission and a receiving apparatus for receiving the signals of theY first transmission released from said storage device and the signals of the delayed transmission from said switching means.

2. A telegraph signaling system for receiving double current cable code radio signals co-nsisting of dots, each represented by power transmission enduring for a whole signal period, of dashes, each represented by ceasing to transmit power for a whole signal period, and of spaces, each represented by power transmission enduring for part of a signal period followed by ceasing to transmit power for the remainder of said signal period, comprising a receiving relay, switching gear driven in step with the received signal periods for converting said double current cable code signals into cable code signals, a pair of relays connected to said switching gear to be actuated by signals o-f one channel, a second pair ofrelays connected to be actuated bythe signals of a second channel, a signal impulse storage device operatively connected to receive and store the signal impulses from saidrst-named pair of relays, a pair or comparison relays for receiving respectively the dot and dash signals from said storage device, a second pair of comparison relays for receiving respectively the dot and dash signals of the second lchannel without storage, a receiving apparatus connected to the contacts of said comparison relays and means for actuating said receiving apparatus to be Vactu-- ated under the control 0f the signals of both channels.

3. A telegraph signaling system for receiving double current cable code radio signals consisting of dots, each represented by power transmission enduring for a whole signal interval, of dashes, each represented by ceasing to transmit power for a whole signal interval, and of spaces, each represented by power transmission enduring for part of a signal interval followed by ceasing to transmit power for the remainder of said signal interval, comprising a receiving relay, switching gear driven in step with the received signal periods for converting said double current cable code signals into cable code signals', a pair of relays connected to said switching gear to be actuated by signals of one channel, a second pair of relays connected to be actuated by the signals of a second channel, a signal impulse storage device operatively connected to receive and store the signal impulses from said iirst-named pair of relays, a pair of comparison relays for receiving respectively the dot and ldash signals from said storage device, a'second pair'of comparisonre.- layscforzrec'eiving respectively the dot andvdash signalsof the second channelwithout stora'gaa receiving apparatus connected tofthecontactsof said comparison relaysand actuatedl under the control-of the signals of both channels, and-a switching devicefor selectively connecting onthe one vhand the contacts of the pair of dot comparison relays in parallel and the 4contacts of the pair of dash comparison relays in series, andrgon the other hand, connecting the contacts of the pair of dot comparison relaysin series Vandthe contacts of the pair of dash comparison-,relays in parallel.

4. A multi-channel telegraph signaling `system for receiving doublecurrent cable codesignals of the type vset forth, comprising in combination, a receiving relay, switch means for con'- verting the double currentc'able code signals into cable code signals .and for separating said signals according to their respective vtransmission channels, 2a signalimpulse storage devicecomprising a'set of condensers and switching-.gear driven in step with the received .signal periods for charging and discharging said condensiers, said storage device being connected tov-be responsive to the, signalsfof one channelanda receiving apparatus common to both channels and connected to receive the signals of one channel released from said storagejdevlcaand the signals of said other channel from said switch means without storage. c f

5.A telegraph signaling systemfor operation with double current cable code signalswofthe type set forth,l comprising in combination, a cable code transmitter, a-signal impulse storage. de- `vice operatively connected to said transmitter, meansfor sending-on signalsy from said cable code transmitter and-said storagedevice, switch; ing gear driven-in step with the signalperiods connected Ato said cable codey transmittensaid storage device and said sending-ori(` meansv and organized to close contacts -tocontrol the -electrical condition of-saidsending-on means sogthat double ,current cable code signals are sent` on from said transmitter and are repeated, after apredetermined time, delay, from saidjstorage-device,

a receiving-relay for receiving the undelayedfand repeated transmissions of the doliblegcurrentV bination, a plurality of cable code transmitters actuated in synchronism with the signals, a signal impulse storage device operatively connected to Ystore signal impulses from one of said cable code transmitters and to' pass on said signal impulses after a predetermined time delay to a second cable code transmitter, means for sending-on signals from said transmitters switching gear driven in step with the signal periods organized t0 pass on the signals from said cable code transmitters to said sending-on means in the form of double-current cable code signals and to allocate the signals 'from the respective cable code transmittersto .separate channels in a predetermined sequence, a

receiving relay, switching means driven in step with the receivedsignal periods for converting the double current cable code signals intocable code signals and for separating said signals according to their respective transmission channels, a second signal impulse storage device operatively connected to said switching means to be responsive to the signals of one channel' and a receiving apparatus common to a plurality of channels and connected to receive the signals of one channel released from said second storage device and the signals of another channel from said switch means without storage.

7. A multi-channel telegraph signaling system for operation with double current cable code signals of the type set forth,` comprising in combination, a plurality of cable code transmitters actuated in synchronism with the signals, means for sending-on signals from said transmitters, a signal impulse storage device comprising a plurality of storage condensers, a plurality of contact segments connected to said condensers, and condenser charging and discharging brushes relatively driven, said charging brushes being connected to one of said cable code transmitters and said discharging brushes to a second cable code transmitter so as to pass on signal impulses stored in said condensers to said second cable code transmitter after a predetermined time delay and switching gear driven in nstep with the signal periods organized to pass on the signals from said cable code transmitters to said sendingon means in the form of double current cable code signals and to allocate the signals from the respective cable code transmitters to separate channels in a predetermined sequence, a receiving relay, switching means driven in step with the received signal periods for converting the double current cable code signals into cable code signals and for separating said signals according to their respective transmission channels, a second signal 'impulse storage device operatively connected to said switching means to be responsive to the signals of one channel and a receiving apparatus common to a plurality of channels and connected to receive the signals of one channel released from said second storage device and the signals of another channel from said switch means without storage.

8. A multi-channel telegraph signaling system for operation with double current cable code signals of the type set forth, comprising in combination, a pair of signaling devices for producing respectively dot and dash cable code signals, an electro-magnetic signal impulse storage device having input circuits connected respectively to 'said signalingdevices, a further pair of signaling -devices respectively 'connected'to' the output circuits of said storage'device, means for sendingon signals produced by said signaling devices, switching gear driven in step with the signal periods organized to pass on theV signals from said signaling devices to said sending-on means in the form of double current cable code signals and to allocate the signals from the respective pairs of signaling devices to separate channels in a predetermined sequence, a receiving relay, switching means driven in step with the received signal periods for converting the double current cable code signals into cable code signals and for separating said signals according to their respective transmission channels, a second signal iinpulse storage device operatively connected to said switching means to be responsive to the signals of one channel and a receiving apparatus common to a plurality of channels and connected to receive the signals of one channel released from said second storage device and the signals of another channel from said switch means Without storage,

9. A multi-channel telegraph signaling system for operation with double current cable code signals of the type set forth, comprising in combination, a pair of signaling devices for producing respectively'dot and dash cable code signals, a mechanical storage device forthe signal impulses comprising a plurality of movable members, a

pair of electromagnets allocated to dots and dashes respectively for setting said members and a pair of contact-closing levers cooperating with said members, means for sending-on the signals produced, switching gear driven in step with the l `the double current `cable code signals into cable code signals and for separating said signals according to their respective transmission channels, a second signal impulse storage device operatively connected to said switching means to be responsive to the signals of one channel and a receiving apparatus common to a plurality of channels and connected to receive the signals of one channel released from said second storage device and the signals of another channel from said switch means without storage.

HARRY VER-,NON HIGGITT. KENNETH LINDSAY WOOD. 

